Subclass (2) Vestibulifera de Puytorac et al., 1974

Syn. Synciliophora s.l.

Cytostome characteristically preceded by a vestibular cavity, latter lined with more or less distinctive ciliature (but ontogenetically of somatic origin); toxicysts rare; syncilia common in one group, and vestibular cilia organized into "cirromembranelles" in another; stomatogenesis basically telokinetal, though apokinetal in the specialized group with synciliary tufts; edaphic and fresh- and salt-water forms, inquilines in echinoids, and endocommensals in herbivorous mammals.

Prostomatine gymnostome-like; vestibular ciliature noncomplex, derived during fission from terminal portions of somatic kineties; cytostome (and vestibulum) sometimes antapical; concrement vacuole present in a few forms; majority of species endocommensals in vertebrate hosts.	Order 1. TRICHOSTOMATIDA Bütschli, 1889
Vestibular and somatic ciliature greatly reduced, appearing only in tufts (though these may be arranged in spiraled bands) and functioning as syncilia; oral area retractable in a number of species; pellicle firm and thickened, often drawn out posteriorly into spines, and body laterally flattened; prominent skeletal plates characteristic of many species; cytoproct distinct; stomatogenesis seemingly apokinetal; widely found as commensals in mammalian (mainly artiodactylan and perissodactylan) hosts, with species of one family in anthropoid apes.	Order 2. ENTODINIOMORPHIDA Reichenow in Doflein & Reichenow, 1929
Some vestibular ciliature organized into two fields of "cirromembranelles"; stomatogenesis, sometimes with discrete primordium, basically telokinetal; body of many species highly asymmetrical, but detorsion before binary or palintomic fission; somatic kinetids typically with kinetosomes in pairs, both ciliferous; macronucleus possibly of low ploidy; cysts common; in freshwater or edaphic (including "terrestrial" and coprophilic) habitats; occasional symbiont in molluscs.	Order 3. COLPODIDA de Puytorac et al., 1974

Incertae sedis in order Trichostomatida or Colpodida:
Grandoria Corliss, 1960 (for Lagenella), enigmatic and sole genus, with single species, in unacceptable family Grandoriidae Corliss, 1960 (for Lagenellidae [for Centrostom(at)idae] )
Opisthostomatella Corliss, 1960 (for Opisthostomum), single species [perhaps bonafide genus in trichostomatid family Marynidae (above)?]
Orcavia Tucolesco, 1962, single (cavernicolous) species;
Rigchostoma Vuxanovici, 1963, single species;
Sigalasza Delphy, 1938, single species;
Sulcigera Gajewskaja, 1933, sole genus, with single species, in perhaps acceptable but unplaceable family SULCIGERIDAE Gajewskaja, 1933 (syn. Sulcigeriidae).